VOIP and powering a router and ONT for 12 hours or more?

[Rollerball]

Due to my location I endure relatively frequent power cuts which can last for hours, if not days. What is the best way to power my ONT and router in the event of a power failure lasting for at least 6 hours or more? This would primarily be for phone use and mainly to handle incoming calls from people who aren't aware that I have a power failure.

Perhaps one of the portable power stations? But they're not cheap, could I somehow leverage the cost out of my ISP ?


My mobile phone signal is spotty which may remove that from the equation, hence the VOIP requirement.

I'm still on copper at the moment but at some time in the past 12 months I'm due to move over to VOIP.

 

[eveares]

High curent car battery charger + car battery + Inverter, maybe?

 

[Harry Bloomfield]

High curent car battery charger + car battery + Inverter, maybe?

Leisure batteries are a better design, for this type of use, or even better a Lithium, or LiPo4. Call it 50w (allowing for inverter, inefficiency) for 10 hours = 500w, or half a Kilowatt hour. 12v x 500 = 42amp/hour battery. Double that, because lead/acid batteries, don't appreciate being discharged, much below 50% capacity, so a 85a/h battery, should easily last you 10 hours.